## Profile

Qiaochu Yuan
Worked at Machine Intelligence Research Institute
Attends University of California, Berkeley
Lives in Berkeley, CA
2,323 followers|150,155 views

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### Qiaochu Yuan

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Among all of the standard algebraic structures that a student typically encounters in an introduction to abstract algebra (groups, rings, fields, modules), commutative rings are somehow special: th...
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Previously we learned how to count the number of finite index subgroups of a finitely generated group $latex G$. But for various purposes we might instead want to count conjugacy classes of finite ...
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After a relaxing and enjoyable break, we're finally in a position to state what it means for structures to satisfy Galois descent. Fix a field $latex k$. The gadgets we want to study assign to each...
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This post really needs pictures. ﻿
Two weeks ago we proved the following formula. Let $latex G$ be a finitely generated subgroup and let $latex a_n$ be the number of subgroups of $latex G$ of index $latex n$. Then \$latex \displaysty...
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Nuts, and now I even know how to draw the pictures. ﻿

### Qiaochu Yuan

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Great stuff!﻿
People
Have them in circles
2,323 people
Work
Occupation
Employment
• Machine Intelligence Research Institute
Visiting Fellow, 2013 - 2013
• PROMYS
Counselor, 2012 - 2012
• Stack Overflow, Inc.
Intern, 2011 - 2011
Places
Currently
Berkeley, CA
Previously
Boston, MA - New York, NY - Bellevue, WA - Nanjing, China - Singapore - Vancouver, WA - Cambridge, UK
Story
Introduction
I'm a third-year graduate student in mathematics at UC Berkeley.
Bragging rights
USA Mathematical Olympiad Honorable Mention (2006), Siemens-Westinghouse Science and Technology Competition Semifinalist (2007), Intel Science Talent Search Finalist (2008), William Lowell Putnam Mathematical Competition Honorable Mention (2009), NSF Fellow (2012)
Education
• University of California, Berkeley
Mathematics, 2012 - present
• Massachusetts Institute of Technology
Mathematics, 2008 - 2012
• University of Cambridge
Mathematics, 2010 - 2011